Closures

ABSTRACT

A pilferproof closure is manufactured so as to have a continuous peripheral score line, internal or external, in place of the conventional line of interrupted slits, and a series of angularly spaced lines of weakness (splits or scores) in the security band. This permits closures of uniform characteristics to be produced by a procedure which involves the formation of the lines of weakness in the security band during the drawing of the shell and the formation of the peripheral line of weakness in a separate manufacturing operation.

United States Patent Hadley Oct. 7, 1975 [54] CLOSURES 2,643,015 6/l953 SOffCl' 215/42 ,4l6,474 12 1968 M [75] Inventor: William Henry Hadley Llchfieldr 3,601 273 si1971 Kriiiirer 215/42 x England [73] Assignee: Metal Closures Limited, West Primary Examiner-Herbert F. Ross BrOmWiCh, England Attorney, Agent, or FirmRoland T. Bryan [22] Filed: Apr. 3, 1973 i Appl. No.: 347,474

Foreign Application Priority Data Apr. 5, 1972 United Kingdom .1 15740/72 US. Cl. 215/252 Int. Cl. B65D 41/34 Field of Search 215/42, 252, 253, 250

References Cited UNITED STATES PATENTS 1/1940 Fabrice 215/42 X [5 7] ABSTRACT A pilferproof closure is manufactured so as to have a continuous peripheral score line, internal or external, in place of the conventional line of interrupted slits, and a series of angularly spaced lines of weakness (splits or scores) in the security band. This permits closures of uniform characteristics to be produced by a procedure which involves the formation of the lines of weakness in the security band during the drawing of the shell and the formation of the peripheral line of weakness in a separate manufacturing operation.

3 Claims, 3 Drawing Figures Jr r H It t U.S. P'itent Oct. 7,1975 Sheet 1 of2 3,910,443

US. Patent Oct. 7,1975 Sheet 2 of2 3,910,443

1 CLOSURES ing theapplication of the closure to;a bottle, engaged under a ribon the bottle neck by a rolling-operation, usually performed simultaneously with the formation of thread in the upper part of the skirt by-a rolling operation. Although it is known to pre-thread closures of the pilferproof type it is usual to thread the closure by the aforementioned thread rolling operation whilst in position on the bottle or other externally threadedcontainer. During the thread rolling operation the closure is subjected to substantial head pressure to bed down the gasket and, where the closure is required .to maintain pressure within the bottle, it is preferred to redraw a short length of the top end of the skirt so as to form a portion of reduced diameter and-to compress an annular portion at the edge of'the gasket'between the reduced diameter portion of the shell of the closure and a cylindrical sealing surface above the thread on the container neck, asdescribed in our BritishPat. No. 975,739. It is, therefore, the practice to form a thickened portion of the gasketat-the angle between the top and the start of the closure shell. This maybe achieved either by flowing in a viscous gasket composition or by reforming an inserted thermoplastic disc.

With the original form of pilferproof closure, as described in British Pat. No.- 369,494, the security band remained in position on the container neck when the closure was unscrewed, breaking the bridges which connect the skirt to the security band.

When pilferproof type closures were applied to reusable bottles for carbonated beverages, the presence of the severed security bands on the bottle necks was very objectionable because of the high cost of removing them before the bottles could be reused.

The original pilferproof closures were employed as a visible guarantee that the contents of the bottle had not been tampered with; for example to guarantee that the contents of a bottle of spirits have not been partially abstracted and replaced by water.

Various forms of pilferproof closure have already been proposed in which the security band is vertically split with the intention that it shall separate automatically from the bottle on unscrewing of the closure. Such forms have relied on the security band remaining attached to the threaded part of the closure by one or more bridges, whilst the remainder of the bridges break.

It has already been proposed to provide a closure of the pilferproof type in which the security band is divided up into a number of separate sections by vertical splits or weakening lines, each section of the security band being connected to the upper part of the closure skirt by two or more bridges. When the closure is unscrewed the separate parts of the security band hinge about the bridges and few, if any, of the bridges are broken. Whilst this type of closure is convenient to replace on the bottle as a reclosure, and, by reason of its construction, ensures that the security band is efiectively removed from the bottle neck, it is of limited effectiveness as a" pilferproof closure, since the separate sections 'of the 'e 'rit band can be'bent inwardly by means of the fingers for re-engagernent under the abutment'rib' on the bottleneck and only careful inspection would reveal that the closure had been unscrewed. It can therefore be rather deceptive to the public, who have come to look onintactbridges as a guarantee of security. Its virtue is that the security band acts as a lock until the closure is deliberately unscrewed.

According to the present invention a closure blank of the type in which the upper part of the closure skirt is engaged with thread on a bottle neck by a thread rolling operation a security band at the lower margin of-the 'skirt is engaged under an abutment ring on the bottle neck is characterised by the fact that the junc-' tion between the security'band and the upper part of the skirt is defined by 'a continuous peripheral score line and that the security band is divided into separate sections by splits or lines of weakness at which the security band opens'out, on unscrewing. I In the productionlof known pilferproof type closures having plural weakening lines in the security band, as referred to above, it is most convenient to form these as internal score line's during the drawing operation for producing the "shell. The internal score lines may be formed by means of sharp-edged formations near the base of the internal forming member, 'so that short score lines are formed in the start of the shell. The peripheral line of slits is'then formed in a separate subsequent operation. It is not practicable to index the bridges in the slit line in relation to the vertical score lines in the security band; In consequence this multiple weakening line type of pilferproof closure is inconsistent in its results, since the performance of the bridges are to some extent dependent upon their positional relationship to the vertical score lines.

When the same technique is employed for forming multiple weakening lines in the security band of a closure in accordance with the present invention, there is no inconsistency in performance since the position of the vertical weakening lines cannot vary in relation to a continuous peripheral score line. This holds true whether the vertical weakening lines are splits, cut right through the security band, or score lines, cut only partially through the security band.

Another advantage of the new closure is that it is ordinarily impossible to remove it without causing some severance of the metal along the peripheral score line. The new closure thus retains the virtue of the known type incorporating plural splits or lines of weakness in the security band whilst reducing the possibility of deceit.

One construction of closure made in accordance with the present invention is illustrated in the accompanying drawing in which,

FIG. 1 shows a closure before application to a bottle and,

FIG. 2 shows the closure after application to the bottle.

FIG. 3 is a section on line IIIIII of FIG. 1.

The closure cap is comprised of a metal shell 1 having an internal gasket 2, which may be formed of flowed-in material or may be a preformed gasket, which is moulded to a predetermined profile after being placed in the cap.

In the operation of drawing the shell 1 a series of vertical score lines 4 are formed in the inner surface of the shell at equal angular positions. Theremay be any number of such score lines, preferablybetween three and I between their upper end and the score line 5. The score line may be formed externally, if desired. The illustrated closure cap is made from aluminium container sheet and the peripheral score line 5 is cut to leave a residual thickness of about 0.004 inches (0.1 mm).

Although score lines 4 are preferably vertical score lines (parallel to the axis of the shell), the score lines I may be formed oblique to the peripheral score line 5 b the use of appropriate tooling.

As an alternative to the formation of the score lines 4 in the security band 6 defined by the score line 5, vertical splits may be formed in place of the score lines 4. In such a case a small uncut tie portion is preferably left at the foot of each split; Whichever alternative is adopted, the security band bursts on at least one of the weakening lines on initial unscrewing. This permits initiation of tearing along the peripheral score line 5, beginning at the upper ends of the burst weakening line.

It will be understood from FIG. 2 that the closure cap of FIG. 1 is engaged with an externally screw-threaded I claim: l. A closure blank of the pilferproof type in which ,the upper part of the closure skirtis adapted to be engaged with the thread on a bottle neck by a thread rolling operation and having a security band at the lower I margin of the skirt which is adapted to be engaged under an abutment ring on the bottle neck wherein the improvement co'mprises'providing a continuous peripheral score line at the junction between the security band and the upper part of the skirt and also dividing 1 the security band into apluralityof separate sections by generally vertical lines of weakness whereby, when said blank has been positioned on a bottle neck with its closure skirt engaged with the thread on a bottle neck and with its security band engaged under the abutment ring on said neck, unscrewing said closure from said bottle and the resulting interaction between said abutment ring and the portion of said security ring which has been engaged thereunder will cause said lines of weak ness to burst open, the lower portions of said sections a to flare noticeably outward, and the continuity between said sections with said upper part of said skirt to be interrupted only ateach end of each section by their being torn apart from said skirt along said score'lin'e so as to present a tangential connection between the segment and the skirt.

2., A closure blank according to claim 1 in which the lines of weakness in the security band are constituted by a plurality of vertical internal score lines.

3. A closure blank according to claim 1 in which the a peripheral internal score line is cut to leave a residual thickness of about 011 mm when the blank is fabricated from'aluminu'm container sheet. 

1. A closure blank of the pilferproof type in which the upper part of the closure skirt is adapted to be engaged with the thread on a bottle neck by a thread rolling operation and having a security band at the lower margin of the skirt which is adapted to be engaged under an abutment ring on the bottle neck wherein the improvement comprises providing a continuous peripheral score line at the junction between the security band and the upper part of the skirt and also dividing the security band into a plurality of separate sections by generally vertical lines of weakness whereby, when said blank has been positioned on a bottle neck with its closure skirt engaged with the thread on a bottle neck and with its security band engaged under the abutment ring on said neck, unscrewing said closure from said bottle and the resulting interaction between said abutment ring and the portion of said security ring which has been engaged thereunder will cause said lines of weakness to burst open, the lower portions of said sections to flare noticeably outward, and the continuity between said sections with said upper part of said skirt to be interrupted only at each end of each section by their being torn apart from said skirt along said score line so as to present a tangential connection between the segment and the skirt.
 2. A closure blank according to claim 1 in which the lines of weakness in the security band are constituted by a plurality of vertical internal score lines.
 3. A closure blank according to claim 1 in which the peripheral internal score line is cut to leave a residual thickness of about 0.1 mm when the blank is fabricated from aluminum container sheet. 